2. Description of Prior Art
Vacuum cleaners are well known and serve an important function in gathering dust and debris in a variety of situations. Household vacuum cleaners, for example, may employ beaters for working dust and debris out of a carpet for removal to a canister or upright style vacuum cleaner collection bag. In certain household systems, a centralized vacuum is provided, wherein the collection-bag and vacuum motor and generation system are located centrally, perhaps in the garage, with the vacuum being routed to various rooms within the house utilizing fixed airflow conduits installed within the walls and accessible in each room utilizing an outlet to which a hose or other vacuum cleaning device can be attached in order to make use of the distributed vacuum. In order to prevent a loss of vacuum from access ports which are not being used for actual vacuum cleaning in a particular time, those ports include covers which serve to block the port, thereby maintaining system vacuum. Vacuum debris removal and collection systems are also useful in shop areas, for example, a home workshop, or industrial shops, such as woodworking shops and machine shops. For example, a number of tools employ dust removal and collection systems. One such tool is a belt driven portable sander, which includes a dust collection bag mounted on it so that as sanding takes place, saw dust is collected within the bag. Other, larger shop machines are designed for permanent or temporary placement at a fixed location, such as a table saws, drill presses, milling machines, joiners, planers, sanders, radial arm saws, and the like. Each of these machines is capable of generating a significant amount of debris and dust in its operation. For this reason, a number of such machines are designed to possibly collect such dust and debris, for example by including within a table saw a box or bin for collecting dust and debris which fall by gravity.
Other ones of these machines are available which include a port for the attachment of a vacuum cleaner hose, such as might be attached to a standard canister-type shop vac which, by means of the vacuum airflow, remove and collect dust and debris. As depicted in FIG. 1, such machines are operated so that the user will manually move the canister-type vacuum cleaner to the general location of the machine to be used and manually attaches a flexible vacuum hose from the canister vacuum cleaner to the machine to be used. The user then turns on the vacuum cleaner and then turns on and utilizes the shop machine, with the vacuum cleaner removing and collecting the dust and debris so generated.
This sort of system is used both in the home or small industrial workshop, for example, by utilizing machines available from Sears Roebuck & Company of Chicago, Ill. which include the vacuum port for the manual attachment of a vacuum hose. This system is also used in larger industrial applications, such as in cabinet making and woodworking shops, in which a canister-type vacuum cleaner or a more sophisticated and expensive sawdust and debris collection machine including a vacuum airflow generator is used in the same fashion, i.e. manually transported through the shop area to the machine to be used, manually connected, manually turned on and off.
As a purported advancement over this prior art, Sears Roebuck & Company has made available, as depicted in FIG. 2, implements for connecting in a permanent fashion a vacuum distribution system capable of supplying a vacuum from a centrally located vacuum airflow device such as a canister-type vacuum cleaner 20 to a plurality of machines 21, 22, 23 located in a small shop area, including manually operated cut-off valves 25, 26, 27 at each machine in order to maintain system vacuum by not applying the system vacuum to other than the single machine being utilized at any given time. However, this system requires each cutoff valve to be manually closed when not in use, a step which is often forgotten. This system also requires each cutoff valve to be manually opened when a machine is turned on, another step which is often forgotten. Yet another disadvantage of this system is that the centrally located vacuum cleaner must be turned on at that central location in order for the debris removal and collection system to operate. Yet another disadvantage is the inconvenient placement of the cutoff valves which, due to the configuration of the carrier ducting, are not easily accessible by the machine operator. This requires extra steps or reaching over or behind a machine to manually operate the cutoff valve, which is likely to be a hazard. In practice, as determined by operational testing, such manually operated cutoff valves are likely to be left open, even when the associated shop tool is not in use, thereby decreasing the amount of vacuum available to shop tools that are actually in use. Such systems also require the vacuum source to be located in or near the shop tool area, to allow for relative ease in allowing a user to manually control the electrical power to the vacuum source. This takes up valuable shop area floor space, and increases the noise in the shop area due to the proximity of the vacuum source.
Larger, more expensive systems include a central vacuum generator and ducting connecting to a plurality of shop machines, and including automatic dampers for connecting the vacuum duct to a specific shop machine only when that machine is turned on. Such electrically or pneumatically controlled dampers are available from Northfab Systems, Inc., of Thomasville, N.C. Such industrial systems are quite bulky and expensive and are designed for use with a large vacuum generation source with large ducting, such as 6 inches or larger for connecting a significant number of machines, any number of which can be in operation at any given time. These automatic dampers are large and expensive, and require pneumatic or electronic controls built in to the rather sophisticated shop tools of such an establishment in order to function properly and automatically.
While the removal and collection of debris and dust may seem merely a nicety, it should be understood that such debris and dust can contribute to a number of significant and costly problems. First of all, dust build-up is a fire and explosion hazard. Secondly, health is adversely effected by breathing and ingesting quantities of dust. Dust and perhaps more significantly small bits of debris flying around a shop area can be a significant nuisance by covering workers with this dust and debris and perhaps cause eye and sinus problems as well. Furthermore, dust covered floors and other surfaces cause safety hazards, such as slippage, and provide an unprofessional appearance to customers and employees. OSHA and other safety standards usually require face masks to reduce such risks but even these requirements, if used at all, are inconvenient and not foolproof.